Neutrinoless double \(\beta \)  decay (\(0\nu \beta \beta \) ) is the process in which two neutrons in a nucleus convert into two protons by emitting two electrons and
no neutrinos [1]}.
This process is by far the most sensitive laboratory probe of lepton number violation (LNV) and
its observation would prove that neutrinos are Majorana fermions [2]},
constrain neutrino mass parameters, and provide experimental validation for leptogenesis scenarios [3]}, [4]}.
If \(0\nu \beta \beta \)  decay is caused by the exchange of light Majorana neutrinos, as we assume throughout this paper, the amplitude is proportional to the effective neutrino mass \(m_{\beta \beta }=\sum _i U_{ei}^2 m_i\) , where the sum runs over light neutrino masses \(m_i\)  and \(U_{ei}\)  are elements of the neutrino mixing matrix. \(0\nu \beta \beta \)  decay is a complicated process encompassing aspects from particle, nuclear, and atomic physics, with the interpretation of current experimental limits [5]}, [6]}, [7]}, [8]}, [9]}, [10]} and of potential future discoveries limited by substantial uncertainties in the calculation of hadronic and nuclear matrix elements [11]}, [12]}, [13]}, [14]}, [15]}, [16]}, [17]}, [18]}, [19]}.
